The Universe as a Simulation

‘Duh huh! That’s putting it mildly!’ Zinda purses her lips. ‘There are two problems, really. The first is that we can’t solve any hard problems. Not really. Anything that’s NP-complete. The Travelling Salesman. Pac-Man. They are all the same. All too hard. Even if we had a computer the size of the Universe! It drives the Sobornost crazy. We don’t mind it so much: that’s what makes most games fun. And we have quantum shortcuts for some special cases, like coordination. And for throwing parties, of course!

‘But if you could do it, things would be very different. You could predict the future. Recreate history. Automate creativity. Make minds truly greater than us. Fulfil all those Strong AI nerd dreams from the pre-Collapse times. So you can see why the Sobornost has been trying for centuries now.’

‘Yes,’ Mieli says, remembering Amtor City, falling, the glowing whirlpool of the singularity, burning in the flesh of Venus.

‘The second problem is that no physical machine we know of can do it. It’s almost like travelling faster than the speed of light, or making a perpetual motion machine. Quantum computers can’t do it, synthbio machines can’t do it, doesn’t matter how big you make them! Pretty early on, everybody agreed that the only place where NP gods could hide was quantum gravity.

‘Use a big enough magnifying glass, and spacetime breaks into tiny pieces. At the Planck scale, causality becomes a variable. You can even have little time machines, closed timelike curves. Nothing like DeLoreans or Grandfather Paradoxes, those don’t fit into quantum mechanics. But maybe you could squeeze a computer in there. And if you could, you could turn time into memory. You could solve NP-complete problems, and more. Sounds too good to be true, right? Right.’

[...]

‘Okay, then,’ Zinda says. ‘Where was I? Oh yes. So, of course, people tried. Pretty early on, too, before the Collapse, with tiny black holes. And they discovered the Planck locks. Try to build a quantum gravity computer, and you get nonsense out. Some say they are artificial, that the Universe is a construct, and the locks were put there to keep us in our place. The old Simulation Argument. But I’m not sure. It could be that they have to be there.’

‘What do you mean?’

‘Think about it. Imagine that there are many possible universes, with different rules. The Spooky-zoku claim that that’s how it works, that there are bubbles of possibility, that they collide and make Big Bangs. So imagine worlds where causal structures are broken, where spacetime can rewrite itself, where there are no stories, no games. Is that a world where we could exist? Is that a world where messy, silly humans arise and stumble through life and build cities and make mistakes? I don’t think so. That would be too tacky. We could not have evolved in a world where the Planck locks do not exist. They have to be there. If they weren’t, we wouldn’t be us.’